Nitrogen incorporation and loss during ion nitriding of Al

Ion nitriding of Al has been performed by a N2 reactive ion beam using a hot filament ion source. Quantitative determination of N incorporation and loss has been estimated at a beam energy of 1.6 keV with two ion current densities of 0.1 and 0.2 mA/cm2 and substrate temperature of 350°C. For this purpose, a characterisation of the ion beam has been carried out by an energy selective mass spectrometer. The analysis shows that the beam consists solely of N2+ and N+ ions with a composition of about 80 % and 20 %, respectively. The ion energy distribution of both N2+ and N+ consists of a single narrow peak with a full width at half maximum of about 10 eV and a mean ion energy corresponding to the applied beam potential. From the beam parameters, N loss due to sputtering and backscattering has been calculated using dynamic binary collision computer simulations. After an initial transient, the stationary partial sputtering yield of N is predicted to be 0.45, while the amount of backscattered N is about 5 % of the incident N fluence. The N loss obtained from the simulation is consistent with the incident fluence and the total amount of incorporated N measured by Nuclear Reaction Analysis (NRA).